The invention relates to an appliance for the surface treatment of coated elements, in particular for the stripping or separation of insulating layers on electrical or optical conductors, in accordance with the preamble of patent claim 1.
An appliance which is used to remove the insulating layer from an insulated conductor is described in U.S. Pat. No. 5,837,961. This appliance has a high-power laser unit, the beam from which is alternately guided, via a plurality of mirrors on two opposite sides of the conductor, onto an insulating layer which is to be removed. The mirrors, which are coupled to a motor via spindles, rods and belts, are for this purpose driven synchronously and moved cyclically.
This known appliance therefore has a complex drive mechanism and relatively expensive mirrors which, at least during production, are to be aligned precisely and subsequently are to be checked and cleaned at regular intervals.
The use of two radiation paths allows more efficient removal of the insulating layers. To increase the number of zones at which insulating material is removed simultaneously, the mirror system would have to be extended, which would entail outlay which is scarcely economically viable.
Furthermore, the controllability of the known appliance is very restricted. If insulating material is to be removed at only one zone, one of the beam paths must, for example, be mechanically interrupted or the mirror drive has to be limited to a selected rotational range.
Therefore, the present invention is based on the object of providing an appliance which can be produced at low cost and is substantially maintenance free and which is suitable for efficient surface treatment of coated elements.
This object is achieved by an appliance which has the features given in claim 1. Preferred configurations of the invention are given in further claims.
The appliance, which is used for surface treatment of coated elements, in particular for separating or removing insulating layers, has at least two laser diodes as laser sources, which are mounted on a mounting body and are or can be oriented in such a manner that the coating of an element can be removed or separated at an intended location.
The laser diodes are mounted on a stable mounting body and are oriented in such a manner that a coated element which has been introduced into the appliance can be exposed to laser beams at the zones provided for this purpose, so that the zone in question can be completely removed or separated by the action of the laser and can be processed using a further tool. By way of example, an insulating layer which is to be removed is separated close to the end of the conductor or cable, where it is mechanically taken hold of by a tool and is then pulled off over the end piece. On the other hand, it is possible for the insulating layer which is to be removed to be scanned or moved over by laser beams until the layer is completely detached.
In this context, it is particularly advantageous, in particular, that there is no need for a system of mirrors, since the laser diodes on the mounting body are oriented or can be oriented by rotation in such a manner that the laser beams can be fed directly, and therefore without attenuation, to the layers which are to be removed. The mounting body can preferably be rotated and/or displaced in the axial direction along the element which is to be processed, so that larger zones can be processed.
The processing rate, which is dependent on the radiation output delivered, can be increased by using a greater number of laser diodes which act simultaneously on different locations of a layer which is to be removed or separated.
By switching off individual laser diodes, it is also possible to effect only partial removal or separation of layers.
By switching off individual laser diodes or reducing the power of individual or all the laser diodes, it is also possible for the radiation power to be adapted to the elements which are to be processed and their coatings, in particular the layer thicknesses.
Furthermore, a deliberate orientation of the laser diodes prevents the laser beam of a laser diode from being able to damage an adjacent laser diode.
In a preferred configuration of the invention, the laser diodes, moreover, are oriented as a function of the dimensions of the elements which are to be processed. The laser diodes are preferably set in such a manner that the laser beams run tangentially with respect to a circle whose radius is selected according to the position and dimension of the coating which is to be removed or separated. The rotational angle of the laser diodes is preferably set in a simple manner by means of a ring which surrounds the mounting body and can rotate relative to the latter.
In a further preferred configuration, the mounting body which is equipped with the laser diodes is selected in such a manner that planar surfaces of an element, for example the sides of ribbon cables or circuit boards on which components are to be mounted, can be processed.
The orientation, movement and operation of the laser diodes or of the mounting body are advantageously controlled by means of a master computer, which simultaneously controls the supply and positioning of the coated elements and, if appropriate, of tools which are used to process the elements.
Furthermore, the material of the mounting body and any mounting means are preferably selected in such a manner that the heat which is generated by power loss is dissipated from the laser diodes. In a preferred configuration, the mounting body also has cooling ribs, by means of which the thermal energy is released to the ambient air, preferably to an air flow which simultaneously serves to extract vapors and particles which may form during the processing of the coated elements.